Until now, the program name of a service was always the file name
(without directory) of the service binary. The program name is used
to, among other things, find the corresponding system.conf entry.
With ASR moving to a situation where all rerandomized service binaries
are stored in a single directory, this can no longer be maintained.
Instead, the service(8) command can now be instructed to override the
service program name, using its new -progname option.
Change-Id: I981e9b35232c88048d8804ec5eca58d1e4a5db82
Please note that this information is for use by system services only!
The clock facility is not ready to be used directly by userland, and
thus, this kernel page extension is NOT part of the userland ABI.
For service programmers' convenience, change the prototype of the
getticks(3) to return the uptime clock value directly, since the call
can no longer fail.
Correct the sys_times(2) reply message to use the right field type
for the boot time.
Restructure the kernel internals a bit so as to have all the clock
stuff closer together.
Change-Id: Ifc050b7bd253aecbe46e3bd7d7cc75bd86e45555
This commits adds a basic infrastructure to support Address Space
Randomization (ASR). In a nutshell, using the already imported ASR
LLVM pass, multiple versions can be generated for the same system
service, each with a randomized, different address space layout.
Combined with the magic instrumentation for state transfer, a system
service can be live updated into another ASR-randomized version at
runtime, thus providing live rerandomization.
Since MINIX3 is not yet capable of running LLVM linker passes, the
ASR-randomized service binaries have to be pregenerated during
crosscompilation. These pregenerated binaries can then be cycled
through at runtime. This patch provides the basic proof-of-concept
infrastructure for both these parts.
In order to support pregeneration, the clientctl host script has
been extended with a "buildasr" command. It is to be used after
building the entire system with bitcode and magic support, and will
produce a given number of ASR-randomized versions of all system
services. These services are placed in /usr/service/asr in the
image that is generated as final step by the "buildasr" command.
In order to support runtime updating, a new update_asr(8) command
has been added to MINIX3. This command attempts to live-update the
running system services into their next ASR-randomized versions.
For now, this command is not run automatically, and thus must be
invoked manually.
Technical notes:
- For various reasons, magic instrumentation is x86-only for now,
and ASR functionality is therefore to be used on x86 only as well.
- The ASR-randomized binaries are placed in numbered subdirectories
so as not to have to change their actual program names, which are
assumed to be static in various places (system.conf, procfs).
- The root partition is typically too small to contain all the
produced binaries, which is why we introduce /usr/service. There
is a symlink from /service/asr to /usr/service/asr for no other
reason than to let userland continue to assume that all services
are reachable through /service.
- The ASR count field (r_asr_count/ASRcount) maintained by RS is not
used within RS in any way; it is only passed through procfs to
userland in order to allow update_asr(8) to keep track of which
version is currently loaded without having to maintain own state.
- Ideally, pre-instrumentation linking of a service would remove all
its randomized versions. Currently, the user is assumed not to
perform ASR instrumentation and then recompile system services
without performing ASR instrumentation again, as the randomized
binaries included in the image would then be stale. This aspect
has to be improved later.
- Various other issues are flagged in the comments of the various
parts of this patch.
Change-Id: I093ad57f31c18305591f64b2d491272288aa0937
VM used to call sendrec to send a boot-time RS_INIT reply to RS, but
RS could run into a pagefault at the same time, thus spawning a
message to VM, resulting in a deadlock. We resolve this situation by
making VM acknowledge RS_INIT asynchronously at boot time, while
retaining the synchronous sendrec for subsequent RS_INIT responses.
Change-Id: I3cb72d7f8d6b9bfdc59a85958ada739c37fa3bde
